Air actuated plastic compound dispensing device

ABSTRACT

An air actuated plastic compound dispensing gun comprised of detachable cylindrical housing and interlocking body member. The housing has two open ends, the forward one of which is circumferentially inwardly flanged. The body member may have one open end and one closed end, the open end of the member being provided with interlocking engagement means to receive and secure therein the cylindrical housing. A cylindrical disposable type plastic filled cartridge is placed in the housing with its forward end protruding through the flanged end of the housing. The cartridge has a forward end dispensing nozzle and a rear end inner wall which wall, with the closed end of the body member, defines a chamber. The body member may be axially orificed through the rear closed end to such chamber, and transversely orificed into said axial orifice. The transverse orifice is connected by means of an adaptive inlet element, to a detachable flexible base supplying pressurized air from an outside source. Disposed in the axial orifice may be a plunger type valve urged to a first rearward position, in which the valve is held open to exhaust to the atmosphere any air pressure in the chamber. When the plunger type valve is pressed forward into said chamber to a second position, the exhaust passage is thereby closed and the pressurized air is conducted to the chamber. Thereupon the pressurized air forces the after end cartridge wall constituting a piston, down the cartridge barrel to extrude the viscous material from the opposite nozzle end.

United States Patent [191 Collar [4 Oct. 7, 1975 AIR ACTUATED PLASTIC COMPOUND DISPENSING DEVICE [75] Inventor: Roland W. Collar, Sun Valley, Calif.

[73] .Assignee: Roean Industries, Pacoima, Calif.

[22] Filed: Jan. 9, 1974 [21] Appl. No.: 432,050

[52] U.S. Cl. 222/327; 222/334; 137/625.48;

'137/625.68 [51] Int. Cl. B67D 5/46 [58] Field of Search 222/389, 327, 258, 261,

Primary ExaminerRobert B. Reeves Assistant ExaminerJoseph J. Rolla Attorney, Agent, or FirmWilliam H. Pavitt, Jr.

[57] ABSTRACT An air actuated plastic compound dispensing gun comprised of detachable cylindrical housing and interlocking body member. The housing has two open ends, the forward one of which is circumferentially inwardly flanged. The body member may have one open end and one closed end, the open end of the member being provided with interlocking engagement means to receive and secure therein the cylindrical housing. A cylindrical disposable type plastic filled cartridge is placed in the housing with its forward end protruding through the flanged end of the housing. The cartridge has a forward end dispensing nozzle and a rear end inner wall which wall, with the closed end of the body member, defines a chamber. The body member may be axially oriflced through the rear closed end to such chamber, and transversely orificed into said axial orifice. The transverse orifice is connected by means of an adaptive inlet element, to a detachable flexible base supplying pressurized air from an outside source. Disposed in the axial. orifice may be a plunger type valve urged to a first rearward position, in which the valve is held open to exhaust to the atmosphere any air pressure in the chamber. When the plunger type valve is pressed forward into said chamber to a second position, the exhaust passage is thereby closed and the pressurized air is conducted to the chamber. Thereupon the pressurized air forces the after end cartridge wall constituting a piston, down the cartridge barrel to extrude the viscous material from the opposite nozzle end.

3 Claims, 8 Drawing Figures US. Patcnt 0a. 7,1975 Sheet 1 of2 3,910,466

US. Patent Oct. 7,1975 Sheet 2 of2 3,910,466

AIR ACTUATED PLASTIC COMPOUND DISPENSING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to devices for dispensing a viscous material, such as a caulking compound, from a cylindrical disposable cartridge, where said cartridge is closed at its after end by a piston-like wall. The invention also pertains to valve means to control the application and exhaust of a pressurized fluid which is intro duced into a device of this type.

2, Description of the Prior Art For many years various forms of plastic material dispensing devices have been manufactured and sold for both industrial and commercial use. A common device heretofore used to dispense viscous materials from disposable cylindrical type cartridges has been a gun-like structure with handle and receptacle into which is fitted and interlocked a detachable cylindrical barrelshaped cartridge housing unit. Such devices have usu ally been fabricated of metal alloys and included a number of intricate and detailed interrelated machined composite parts.

In more recent years, however, dispensing devices of the type referred to have been fabricated of plastics having fewer movable or interrelated parts, thus providing expediency in manufacturing techniques and inexpensive replacement of parts. Further, the use of pastic materials has facilitated the improvement of valve mechanisms designed to control the feed and flow rates of viscous materials from the nozzle end of the cartridge, thereby precluding waste of such materials, par: ticularly where such waste has resulted from pressure overloads or inaccurate pressure control mechanisms. In the latter devices, the valve means have been designed to be pressure controlled by spring tension means disposed to automatically open or exhaust when the applied pressure exceeded a predetermined value in pounds per square inch (p.s.i.), said precalculated spring tension means thereby preventing overloading of the pressurizable chamber so that only minimal waste of the viscous material would occur.

While prior art methods have vproven both feasible and acceptable for industrial and commercial use, the various configurations and designs of prior art control means to regulate pressure have presented several problems.

In the first place, if the valve mechanism is fabricated from metal alloys as a component of a metallic housing unit, the tolerances for interconnectable and interelated parts are stringent, thereby resulting in expensive and tedious machining operations; also, the use of metallic valve systems coupled with other metallic component members of the device results in a cumbersome and heavy unit which becomes awkward to use and fatiguing for the operator, and especially where operations necessitate overhead use of the device. A further problem associated with metal alloys is the necessity of maintaining and cleaning the metallic components to preclude corrosion and freezing of movable metal parts thereby resulting in inoperability of the device. Replacement of intricate machined metal components or valve systems is also expensive.

Secondly, although the use of plastic fabricated housing, adapters and valving means for pressurized dispensing ofviscous materials from disposable cartridges has alleviated some of the aforesaid expense and corrosion related problems, certain other associated problems have not heretofore been eliminated. The present state of the art relative to plastic fabricated components for dispensing devices, including valving means for pressure control, has been such that the valving means comprise elaborate and intricate design configurations which must be operably retained in an interconnected relationship and disposed in a reciprocal movable position in conjunction with a pressurizable chamher. The design configurations have encompassed varying degrees of bevels, flanges, valve stems, valve seats, springs of precalculated resistance forces, all of which have had to be intricately fabricated and then assembled into a unitary functioning component by bonding, threaded engagement means or the like. This valve complexity has required 'a high degree of skill and know-how properly to assemble and service the devices, and has made even the plastic devices unusually costly to fabricate and sell.

In addition, where low viscosity materials require only minimal p.s.i. forces for dispensing purposes, the use of inexpensive diaphragm type compressors has heretofore been untenable. Stalling of this type compressor has been a persistent commonplace problem due to inadequate exhaust means or capable by-pass mechanisms in the valving system to prevent pressure buildup. The precalculated tension actuated means for modulated exhaustion has not been effectively 0r adequately controllable in the low p.s.i, ranges to preclude the stalling of diaphragm type compressors.

Finally, the design features inherent in prior art valving systems which have been directed to regulating and controlling the air pressure have resulted in excessive costs in replacing malfunctioning, defective or fatigued valve systems and valve housing mechanisms,

SUMMARY OF THE INVENTION The present invention avoids the above described disadvantages of prior art dispensing devices and valve systems for dispensing viscous materials from disposable cartridges by being so constructed that atmospheric exhaustion of air pressure is continuous until required for application to the rear wall of the pistonlike cartridge. Moreover, the pressure may be controlled to effect dispensing without the aid of precalculated tension means for modulated atmospheric exhaustion of fluid pressure. Further, fabrication of the improved valve system is less intricate and less expensive than prior art designs or configurations.

In one embodiment of the invention, a body member is provided with an axially oriented plunger type valve which is biased to a first position by fluid pressure, wherein said valve circumferentially continuously exhausts to the atmosphere a transversely entering pressurized fluid stream (such as air or other gas), and upon depression of said plunger type valve from the rear of the adapter member, the valve is, shifted from its said first position by sliding forward in its axial orifice through the body member to a second position wherein the circumferential atmospheric exhaust path is closed and the pressure fluid stream is diverted to and against the rear wall of the disposable cartridge held adjacent the adapter by the cartridge housing barrel. Thereupon, the said inner cartridge wall is forced by the pressurized fluid as a piston down the cylindrical cartridge to extrude the plastic material in the cartridge from the nozzled outer end of the cartridge. Release of the valve plunger results in its return by the pressure fluid to the first position of the valve where atmospheric: exhausting again occurs.

Ina second embodiment of the invention, the body member is also provided with an axially oriented I tion wherein the axial passage between the said chamber, and the atmosphere is closed; and simultaneously the pressure fluid is directed circumferentially about the valve into said chamber where it exerts force against the rear wall of the disposable cartridge, thereby to drive said inner wall in a piston-like manner down said cartridge barrel to extrude the plastic material, in the cartridge from the nozzled outer end of the cartridge. Releasing the valve plunger causes immediate return of the valve to its first position through the spring bias, thereby simultaneously shutting off the flow of pressure fluid to the chamber and placing the latter in communication with the atmosphere.

By so providing such improved and simple valving systems, which may be expeditiously fabricated and readily utilized with the body member and disposable cartridge housing members, an inexpensive totally plastic dispensing device may be fabricated at a very low cost. Because of the simple design and the low cost of replacing component parts, it is unnecessary for users of the device to take great care of the device.

Further, in dispensing with prior art valving mechanisms, not only is the cost reduced, but use of the valving mechanisms of the present invention facilitates ease of handling and operabili'ty; and finally, malfunctioning of the valving mechanism is minimal due to the simplicity of construction and fabrication from plastic polymers.

In a number of important respects, therefore, the

present invention overcomes the problems inherent in prior art valving mechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is an enlarged section, taken on the line 2'2 of FIG. 1 with the valve means shown in one of the two positions.

FIG. 3 is a partial section similar to FIG. 2 but with the valve means shown in the other of its two positions.

FIG. 4 is a cross-section taken on lines 4,4 of FIG. 2.

FIG. 5 is a perspective view of a second embodiment of the present invention.

FIG. 6 is an enlarged section taken on the line 6--6 of FIG. 5 with the valve means shown in its closed position. I

FIG. 7 is a partial section similar to FIG. 6 but with valve means shown in open position.

FIG. 8 is a perspective viewv of the Button-Valve shown cross sectionally in FIGS. 6 and 7.

DESCRIPTIQN OF THE PREFERRED EMBODIMENT Referring to FIG. I of the drawings, a fluid actuated gun type dispensing device constructed in accordance with the present invention may be comprised of a body member 10 into which may be interlockingly inserted a cylindrical adapter housing 12 which is orificed at14 in its opposite end 16 and receives and holds a disposable plastic filled cartridge 18 therein. Such a cartridge comprises a cylindrical shell 18a which is nozzled at 1817 at one end 18c and is provided with a piston-type closure 18d at its opposite end 186. When the cartridge 18 is thus inserted in the adapter housing 12 and the latter interlocked into the body member 10 against a sealing ring 13, a chamber .15 will be foundtobe defined by the walls of the piston closure 18d and the inner transverse wall 10a of the body member 10.

The body member 10 includes an integrally formed handle 20 which is orificed at 22 to provide an air inlet passage as shown in FIGS. 2 and 3. The outer end 24 of this orifice may be threaded at 26 to provide for screwing on a base fitting 28 (FIGS. 1 and 2). The base I fitting is provided with adaptive means 30 for attachment to a flexible hose 32 (FIG. 1) which supplies pressurized air from a compressor or other outside source a (not shown).

The body member 10 is axially orificed at 34 slidably to receive a plunger-type valve 36. The orifice 34 is counterbored at 38, a predetermined distance, to allow a coiled spring element 40 to be seated on the shoulder 42 where the orifice 34 and counterbore 38 join. The

valve 36 may be circumferentially grooved at 44 to receive and hold therein a retaining ring 46 at the forward end 36a of said valve 36. The valving means 36 may be further circumferentially grooved at 48, 48a,

and 48b to receive respectively sealing O-rings 50, 52 and 54. A furtherv circumferential recess 55 is provided about the valve member 36 and an axial bore 56 extends between the end 36a and diametric passage 58 disposed toward the rear of the valve .36.

As shown in FIGS. 2 and 4, when the valving mechaward position relative to the body member 10. In this rearward position the retaining ring 46 is held against the rear innerwall 10a of the body member 10.. In such rearward position, the pressurized fluid which enters through the handle orifice 22'is prevented from passing beyond the circumferential groove 55 about the valve member 36.

Upon pushing the plunger-type valve 36 forward to a second position as shown in FIG. 3, the retaining ring 46 is moved away from the inner rear wall 10a. In this second position, the axially bored valve orifice 56 and the transversely bored valve passage 56 are closed, precluding atmospheric exhaustion or bleeding of the pressurized air from the chamber I5. Simultaneously the groove 55 is shifted to where one end 55a is opened to the chamber 15, while the other end 5519 is open to the small orifice 22a connected to the orificed handle pas-, sage 22. The circumferentially ringing sealing elements 52 and 54 prevent escape of air to the atmosphere while the plunger valve 36 is held in this second position A similar valving arrangement, as shown in FIGS. 5-8, may be provided for use with small diaphragm type compressors utilized as an air supply source and especially where low viscosity materials are to be dispensed. In this embodiment a unitary thumb button: type valve 70 may be provided. The valve 70 may be slidably disposed in an axial orifice 72 in a cup-shaped body member 74. The body member 74 may be provided with threaded engagement means 76 to receive and hold therein a cylindrical retainer housing 77 within which is contained a plastic-filled disposable cartridge 76:: having a movable rear piston wall 78 similar to what has been described above in connection with the FIGS. 1-4 embodiment of the present invention and is well known in the art.

The axial orifice 72 of the body member 74 is counterbored at 80. Further, the body member 74 is transversely bored at 88, and counterbored at 88a and may be threaded at 89 a sufficient distance to receive in said counterbore 88:: a base fitting 84 which may be screwed therein, and is connectable by a hose 86, to a pressurized air source, such as a diaphragm type compressor (not shown).

The configuration of the valve member 70 is such that its diameter, for the axial distance .r-y, enables it to be loosely slidable with a small amount of clearance within the wall-defining the orifice 72; and toward the rear end of such member 70 for the distance .t v', the diameter thereof is increased to where such portion slides closely within the counterbore 80. The member 70 may be further circumferentially grooved at 91 to receive an O-ring 81. The forward end 70aofthe valve member may be slotted at 70!) for a predetermined distance D-E for two purposes: first, by slotting the end 700, the end may be provided with an enlargement in the form of an opposed pair of co-planar semicircular terminal plates 82 and 82:! which, after they are first pressed together and passed through the orifice 72,

snap apart to prevent the member 70 from being blown back out of the orifice 72 when air under pressure is admitted through the passage 88; and secondly, the slotting 70h places the chamber in continuous communication with the space surrounding the axial section of the valve member 70, into which space the pressure airis admitted through the passage 88.

It will be noted that, in the FIGS. 5 8 embodiment of the invention, no spring is provided to bias the button valve 70 rearwardly. Because of the valve arrangement selected, no bias is required. As soon as air under pressure is admitted through the passage 88 or is retained in the chamber 15, the valve body 70 is subjected to a continuous force pushing it to the rear so that the pressure air may be exhausted to the atmosphere through the clearance space surrounding the v portion of the valve body 70 and the counterbore 80. The member 70 is thus maintained in its first rearwardly disposed position so long as air pressure is present in the bore 72. This first position continuously bleeds the transversely entering pressurized air so that I when a small diaphragm type compressor is used, the compressor may be started without stalling the motor. It is only when such air pressure force is overcome by a greater force being applied by an operators thumb to the rear of the button valve 70 that the passage through such clearances and the counterbore 80 is closed by the O-ring 81 being pressed against the *shoulder between the bore 72 and counterbore 80. At this point, the pressure air is diverted exclusively into the chamber 15', thereby to force the piston 78 down the cartridge barrel 76a to extrude the cartridge contents out of the nozzle 86.

The embodiments of the invention as shown in FIGS. 1 through 8 are particularly advantageous in that the above described valving means may be fabricated and assembled more easily, and hence muchmore inexpensively than prior art means. Exhaustion of fluid pressure ,is immediate, actuation and dispensing is precise and accurately controllable without exotic precalculated physical characteristics and compared to prior art valving means, the embodiments disclosed herein are inexpensive to manufacture, maintain and replace.

The invention is not limited to the embodiments described above, but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.

Having described the invention, what'is claimed is: 1. An air actuated device for dispensing a viscous material contained in a disposable cartridge in the form of a cylindrical-walled barrel having a nozzle outlet at one end of the barrel and a piston closure at the other end of the barrel, said device'comprising: i A. a cylindrical housing dimensioned to receive in a close fit and toretain'said cartridge, said housing being partially closed but orificed centrally at one end to permit the cartridge nozzle to extend through said orifice, and the other end of said housing being" open and' provided with interlocking means; B. a receptacle body member for receiving and securing the said other end of said housing therein, said receptacle body member having (i) a cylindrical socket cavity with an open end and a'closed end, to receive the said other end of said housing after one of said cartridges has been inserted in said housing, and (ii) means cooperating with said interlocking means to removably secure said housing end in said socket cavity and in abutment with. the portion of the body member defining said cavity, an orifice in said receptacle body member, said orifice extending axially therethrough from the socket cavity to communicate with a counterboreextendirig coaxially from the after end of said socket, and said receptacle body member being transversely orificed from said axial orifice to a point outside said receptacle body member to provide an air inlet passage connectable to a source of air under pressure; and C. a plunger type valve, said valve being slidably disposed in said axial orifice and counterbore and extending from said socket cavity to a point beyond the after end of said body member, said valve being axially orificed from its socket cavity end to a point on said valve in said counterbore, and a transverse bore in said valve at the last said point, and said valve further having a pair of axial extents spaced from each other and fitting closely in said orifice, and an intermediate axial extent between said pair of axial extents of lesser diameter than that of said orifice to constitute an annulus in said plunger valve, and said valve being provided with means at its end extending into the socket cavity to prevent said end from being drawn into said axial orifice,

said valve being slidable in said axial orifice from a first position into which said valve is biased,-

lus is placed, in communication with both said socket and said air inlet passage and venting through said axial valve orificeis prevented by shifting the transversely bored valve area inwardly from said counterbore into said axial orifice, thereby, while said venting. is thus prevented, the air under pressure is directed into said socket behind said cartridge piston to build uppressure in said socket, to force the said piston down the cartridge barrel within said cylindrical housing to extrude the viscous material through the cartridge nozzle.

2. An air actuated device for dispensing a viscousmaterial contained in a disposable cartridge in the form of a cylindrical-walled barrel having a nozzle outlet at one end of the barrel and a piston closure at the other end of the barrel, said device comprising:

A. a cylindrical housing dimensioned to receive in a close fit and to retain said cartridge, said housing being partially closed but orificed centrally at one end to permit the cartridge nozzle to extend through said orifice, and the other end of said housing being open and provided with interlocking means;

13. a receptacle body member for receiving and secur ing the said other end of said housing therein, said receptaclebody member having (i) a cylindrical socket cavity with an open end and a closed end, to receive the said other end of said housing after one of said cartridges has been inserted in said housing, and (ii) means cooperating with said interlocking means to removably secure said housing end in said socket cavity and in abutment with the portion of the body member defining said cavity, an orifice in said receptacle body member, said orifice extending axially therethrough from the socket cavity to communicate with a counterbore extending eoaxially from the after end of said socket, and said receptacle body member being transversely orificed from said axial orifice to a point outside said receptacle body member to provide an air inlet,

passage connectable to a source of air under pressure; and I C. a plunger type valve, said valve being slidablyidisposed in said axial orifice and counterbore and extending from said socket'cavity to a point beyond the after end of said body member, and said valve having a sufficiently lesser diameter than that of said orifice to provide an annular passage between the wall defining said orifice and said valve, said passage communicating at all times with the socket cavity, said valve being provided with means at its end extending into the socket cavity to prevent said end from being drawn into said axial orifice, and with means at its outer end when said valve end is pushed into the counterbore toshut off communication between said annular passage and the atmosphere through said counterbore, said valve being slidablein said axial orifice from a first position into which said valve is biased by the air under pressure arriving in said annular passage through 7 said transverse orifice, wherein said air under pressure entering said annular passage is vented through said counterbore and hence cannot build up pressure in said socket cavity; to a second position forwardly of said first position accomplished by being manually pushed into said body member from the rear thereof against the airpressure bias wherein the annular passage is closed off venting to the atmosphere through the counterbore, so that the air under pressure is directed into and confined within said socket cavity behind saidcartridge piston to build up pressure in said socket cavity, thereby forcing the said piston down the cartridge barrel within said cylindrical housing to extrude the viscous material through the cartridge nozzle.

3. The device as described in claim 2 wherein the forward end of the plunger valve is bifurcated and provided with retaining elements of such dimensions as to, when pressed radially inwardly, enable said elements to pass through said axial orifice; but aftermpassing, 

1. An air actuated device for dispensing a viscous material contained in a disposable cartridge in the form of a cylindricalwalled barrel having a nozzle outlet at one end of the barrel and a piston closure at the other end of the barrel, said device comprising: A. a cylindrical housing dimensioned to receive in a close fit and to retain said cartridge, said housing being partially closed but orificed centrally at one end to permit the cartridge nozzle to extend through said orifice, and the other end of said housing being open and provided with interlocking means; B. a receptacle body member for receiving and securing the said other end of said housing therein, said receptacle body member having (i) a cylindrical socket cavity with an open end and a closed end, to receive the said other end of said housing after one of said cartridges has been inserted in said housing, and (ii) means cooperating with said interlocking means to removably secure said housing end in said socket cavity and in abutment witht the portion of the body member defining said cavity, an orifice in said receptacle body member, said orifice extending axially therethrough from the socket cavity to communicate with a counterbore extending coaxially from the after end of said socket, and said receptacle body member being transversely orificed from said axial orifice to a point outside said receptacle body member to provide an air inlet passage connectable to a source of air under pressure; and C. a plunger type valve, said valve being slidably disposed in said axial orifice and counterbore and extending from said socket cavity to a point beyond the after end of said body member, said valve being axially orificed from its socket cavity end to a point on said valve in said counterbore, and a transverse bore in said valve at the last said point, and said valve further having a pair of axial extents spaced from each other and fitting closely in said orifice, and an intermediate axial extent between said pair of axial extents of lesser diameter than that of said orifice to constitute an annulus in said plunger valve, and said valve being provided with means at its end extending into the socket cavity to prevent said end from being drawn into said axial orifice, said valve being slidable in said axial orifice from a first position into which said valve is biased, wherein said air under pressure entering said body member through said transverse orifice is confined to said annulus and is thereby prevented from developing a pressure force in said socket cavity through said axial orifice, and said socket cavity is vented through the axial orifice in said valve to the atmosphere in said counterbore at the rear of said body member, to a second position, accomplished by being pushed manually forwardly into said body member from the rear thereof, wherein said annulus is placed in communication with both said socket and said air inlet passage and venting through said axial valve orifice is prevented by shifting the transversely bored valve area inwardly from said counterbore into said axial orifice, thereby, while said venting is thus prevented, the air under pressure is directed into said socket behind said cartridge piston to build up pressure in said socket, to force the said piston down the cartridge barrel within said cylindrical housing to extrude the viscous material through the cartridge nozzle.
 2. An air actuated device for dispensing a viscous material contained in a disposable cartridge in the form of a cylindrical-walled barrel having a nozzle outlet at one end of the barrel and a piston closure at the other end of the barrel, said device comprising: A. a cylindrical housing dimensioned to receive in a close fit and to retain said cartridge, said housing being partially closed but orificed centrally at one end to permit the cartridge nozzle to extend through said orifice, and the other end of said housing being open and provided with interlocking means; B. a receptacle body member for receiving and securing the said other end of said housing therein, said receptacle body member having (i) a cylindrical socket cavity with an open end and a closed end, to receive the said other end of said housing after one of said cartridges has been inserted in said housing, and (ii) means cooperating with said interlocking means to removably secure said housing end in said socket cavity and in abutment with the portion of the body member defining said cavity, an orifice in said receptacle body member, said orifice extending axially therethrough from the socket cavity to communicate with a counterbore extending coaxially from the after end of said socket, and said receptacle body member being transversely orificed from said axial orifice to a point outside said receptacle body member to provide an air inlet passage connectable to a source of air under pressure; and C. a plunger type valve, said valve being slidably disposed in said axial orifice and counterbore and extending from said socket cavity to a point beyond the after end of said body member, and said valve having a sufficiently lesser diameter than that of said orifice to provide an annular passage between the wall defining said orifice and said valve, said passage communicating at all times with the socket cavity, said valve being provided with means at its end extending into the socket cavity to prevent said end from being drawn into said axial orifice, and with means at its outer end when said valve end is pushed into the counterbore to shut off communication between said annular passage and the atmosphere through said counterbore, said valve being slidable in said axial orifice from a first position into which said valve is biased by the air under pressure arriving in said annular passage through said transverse orifice, wherein said air under pressure entering said annular passage is vented through said counterbore and hence cannot build up pressure in said socket cavity; to a second position forwardly of said first position accomplished by being manually pushed into said body member from the rear thereof against the air pressure bias wherein the annular passage is closed off venting to the atmosphere through the counterbore, so that the air under pressure is directed into and confined within said socket cavity behind said cartridge piston to build up pressure in said socket cavity, thereby forcing the said piston down the cartridge barrel within said cylindrical housing to extrude the viscous material through the cartridge nozzle.
 3. The device as described in claim 2 wherein the forward end of the plunger valve is bifurcated and provided with retaining elements of such dimensions as to, when pressed radially inwardly, enable said elements to pass through said axial orifice; but after passing through the axial orifice and entering the socket cavity, said elements expand and prevent the valve plunger from being blown out of the axial orifice by air pressure. 